[Mac] Disable all sandboxd logging unless running with --enable-sandbox-logging.

chrome/common/common.sb

Index: chrome/common/common.sb
diff --git a/chrome/common/common.sb b/chrome/common/common.sb
index 71c73cf48b991d4903f1f87f129d798bb21aded2..f8d4f1ceba6bb064f073a01bb02fbc087aa2957e 100644
--- a/chrome/common/common.sb
+++ b/chrome/common/common.sb
@@ -3,10 +3,15 @@
 ;; Use of this source code is governed by a BSD-style license that can be
 ;; found in the LICENSE file.
 ;;
-; This configuration file isn't used on it's own, but instead implicity included
-; at the start of all other sandbox configuration files in Chrome.
+; This configuration file isn't used on it's own, but instead implicitly
+; included at the start of all other sandbox configuration files in Chrome.
 (version 1)
-(deny default)
+
+; DISABLE_SANDBOX_DENIAL_LOGGING expands to syntax that turns off log message
+; printing on sandbox exceptions; this functionality only exists on 10.6. The
+; --enable-sandbox-logging flag or system versions <10.6 cause this flag to
+; expand to an empty string. http://crbug.com/26621
+(deny default DISABLE_SANDBOX_DENIAL_LOGGING)
 
 ; Support for programmatically enabling verbose debugging.
 ;ENABLE_LOGGING (debug deny)